Hey guys

I did a search but could only find stuff more about the rarity and value of MC18 SPs.

I have a chance to maybe get a mc18 SP for a good price. I think its the earlier model ('88). I'd just like to know what makes a mc18sp different from regular mc18s? and regarding the value as a potential collector's piece, what would determine whether it's worth a lot, or not so much?

Thanks!